Science

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Across
  1. 3. A type of organism that no longer exists
  2. 5. the magma cools and hardens into a mass of igneous rock
  3. 6. a gap in the geologic record
  4. 8. a fixed point in time from which a series of years is reckoned
  5. 10. scientists who study fossils
  6. 13. the change in living things over time
  7. 15. age The relative age of rock is its age compared to the ages of the other rocks
Down
  1. 1. lava hardens on the surface and forms igneous rock
  2. 2. eras are subdivided into units of geologic time
  3. 4. age The absolute age of a rock is the number of years that have passed since the rock formed
  4. 7. decay the process of elements release particles and energy
  5. 9. life
  6. 11. a ball of dust, gas, and ice orbits the sun
  7. 12. preserved remains or traces of living things
  8. 14. time scale A record of the geologic events and the evolution of life forms as shown in the fossils record